Method for forming a gas phase in water saturated hydrocarbon reservoirs

Abstract

The present disclosure describes a method of recovering oil and gas from a hydrocarbon-containing reservoir generally having some degree of water saturation within the reservoir pore network by injecting a gas into the reservoir. The method applicable to reservoirs having high water saturation of about 50 percent or greater. High water saturation in a reservoir can cause excessive amounts of water to be produced to produce the hydrocarbons. Coproduction and management of this water is costly and burdensome to operations leaving many reservoirs of oil and gas are stranded, rendering the production uneconomic. The method described herein addresses this need and other needs. The injection gas (with or without other hydrocarbons) can coalesce with the hydrocarbons contained within the hydrocarbon-containing reservoir to form a continuous phase of hydrocarbons within the reservoir. Once the targeted volume of the injection gas is injected, the flow is reversed producing the gathered hydrocarbons.

What is claimed is: 
     
         1 . A method, comprising:
 providing a gas;   injecting the provided gas into a selected well bore in fluid communication with a hydrocarbon-containing reservoir having a first water-to-gas production ratio, wherein the hydrocarbon-containing reservoir comprises a gaseous hydrocarbon, wherein the provided gas is injected at rate of from about 10 mcfd or more to about no more than about 8,000 mcfd, and wherein at least most of the hydrocarbons produced by the well bore are gaseous hydrocarbons;   ceasing the injection of the provided gas into the selected well bore; and   gathering together from the hydrocarbon-containing reservoir by the selected well bore some of the provided gas and some of the gaseous hydrocarbons to form a gathered-gas mixture comprising the provided gas and some of the gaseous hydrocarbons from the hydrocarbon-containing reservoir; and   producing through the selected well bore the gathered-gas mixture, wherein the hydrocarbon-containing reservoir producing the gathered-gas mixture has a second water-to-gas production ratio and wherein the second water-to-gas ratio is no more than the first water-to-gas ratio.   
     
     
         2 . The method of  claim 1 , wherein the provided gas injected into the hydrocarbon-containing reservoir is selected from the group consisting essentially of methane, ethane, propane, nitrogen, butane, air, oxygen, argon, carbon dioxide, helium or mixture thereof and wherein, immediately before and after provided gas injection, at least about 75 mole % of the hydrocarbons produced from the selected well bore are gaseous hydrocarbons. 
     
     
         3 . The method of  claim 1 , wherein, prior to the injecting of the provided gas, the hydrocarbon-containing reservoir comprises a plurality of discrete hydrocarbon phases, wherein the plurality of discrete hydrocarbon phases is in the form of one or more pockets and bubbles of hydrocarbons, wherein the injecting of the provided gas coalesces the one or more of the plurality of discrete hydrocarbon phases into one or more continuous hydrocarbon phases. 
     
     
         4 . The method of  claim 1 , wherein the gathered gas mixture comprises the provided gas and the gaseous hydrocarbons having from about 2 to about 98 volume % of the provided gas and from about 98 to about 2 volume % of the gaseous hydrocarbon. 
     
     
         5 . The method of  claim 1 , wherein the gaseous hydrocarbon comprises one of methane, ethane, propane, n-butane, isobutane, ethylene, propylene, 1-butene, and mixture thereof. 
     
     
         6 . The method of  claim 1 , wherein the first water to gaseous hydrocarbon is from about 1 bbl water/1000 MCF to about 2000 bbl water/1000 MCF. 
     
     
         7 . The method of  claim 1 , wherein the second water to gaseous hydrocarbon ratio is from about 98% to about 2% of first water to gaseous hydrocarbon ratio. 
     
     
         8 . The method of  claim 1 , wherein the injecting of the provided gas is for a period from about five days to about three months. 
     
     
         9 . The method of  claim 1 , wherein the gaseous hydrocarbon gas comprises methane. 
     
     
         10 . A method, comprising:
 providing a well producing gaseous hydrocarbons having first water to gas production ratio;   providing a gas;   injecting the provided gas into a well bore, wherein the well bore is in fluid communication with a hydrocarbon-containing reservoir, wherein the hydrocarbon-containing reservoir comprises a gaseous hydrocarbon;   ceasing the injection of the provided gas; and   producing from the well bore a mixture of the provided gas and some of the gaseous hydrocarbons having a second water to gas production ratio, wherein the first water-to-gas ratio is greater than the second water-to-gas ratio and wherein the hydrocarbons produced from the well bore in the producing step are predominately gaseous hydrocarbons.   
     
     
         11 . The method of  claim 10 , wherein the hydrocarbon-containing reservoir comprises pore volumes having a porosity and permeability, and wherein, prior to the injecting of the provided gas, the hydrocarbon-containing reservoir comprises a plurality of discrete hydrocarbon phases contained within the pore volumes and wherein the injecting of the provided gas coalesces the one or more of the plurality of discrete hydrocarbon phases into one or more continuous hydrocarbon phases, and wherein the one or more continuous hydrocarbon phases span three or more pore volumes. 
     
     
         12 . The method of  claim 11 , wherein the gaseous hydrocarbon comprises one of methane, ethane, propane, n-butane, isobutane, ethylene, propylene, 1-butene, and mixture thereof and wherein, immediately before and after provided gas injection, at least about 75 mole % of the hydrocarbons produced from the selected well bore is a gaseous hydrocarbon. 
     
     
         13 . The method of  claim 10 , wherein the first water to gaseous hydrocarbon is from about 1 bbl water/1000 MCF to about 2000 bbl water/1000 MCF. 
     
     
         14 . The method of  claim 10 , wherein the provided gas injected into the hydrocarbon-containing reservoir is one of methane, ethane, propane, nitrogen, butane, air, oxygen, argon, carbon dioxide, helium or mixture thereof. 
     
     
         15 . The method of  claim 10 , wherein the injecting of the provided gas into the well bore is at a pressure below the fracture press of the hydrocarbon-containing reservoir. 
     
     
         16 . The method of  claim 10 , wherein the second water to gaseous hydrocarbon ratio is from about 98% to about 2% of first water to gaseous hydrocarbon ratio. 
     
     
         17 . The method of  claim 10 , wherein the mixture of the provided gas and some of the gaseous hydrocarbons comprises from about 2 to about 98 volume % the provided gas and from about 98 to about 2 volume % the gaseous hydrocarbon. 
     
     
         18 . The method of  claim 10 , wherein the injecting of the provided gas is for a period from about five days to about three months. 
     
     
         19 . A method, comprising:
 providing a target well having a first water to gas production ratio from about 1 bbl water/1000 MCF to about 2000 bbl water/1000 MCF;   providing a gas;   injecting the provided gas into a well bore, wherein the well bore traverses and is in fluid communication with the hydrocarbon-containing reservoir, wherein the provided gas is injected at a rate of from about 10 mcfd or more to about no more than about 8,000 mcfd, and wherein at least most of the hydrocarbons produced by the well bore is a gaseous hydrocarbon; and   producing, after the ceasing of the injection of the provided gas, from the target well at a second water to gaseous hydrocarbon ration, wherein the second water to gaseous hydrocarbon ratio is from about 98% to about 2% of first water to gas production ratio and wherein hydrocarbons produced from the well bore in the producing step are at least most gaseous hydrocarbon.   
     
     
         20 . The method of  claim 19 , wherein the provided gas injected into the hydrocarbon-containing reservoir is one of methane, ethane, propane, nitrogen, butane, air, oxygen, argon, carbon dioxide, helium or mixture thereof and wherein the injecting of the provided gas into the well bore is at a pressure below the fracture press of the hydrocarbon-containing reservoir and wherein, immediately before and after provided gas injection, at least about 75 mole % of the hydrocarbons produced from the well bore is a gaseous hydrocarbon.